This study is researching an experimental drug called linvoseltamab combined with another drug called dupilumab. The study is looking at patients who have severe IgE-mediated food allergy. If the patient has an allergy, the body's defense system (immune system) overreacts to an allergen (eg, certain foods like peanuts, milk, shellfish) by making antibodies called IgE. An antibody is a protein that allows the immune system to find and fight off things the body does not recognize (allergens). IgE antibodies are sent out by cells like plasma cells. These antibodies and allergens bind to other cells that send out chemicals, causing an allergic reaction. The aim of the study is to see what side effects happen when linvoseltamab is combined with dupilumab. The study is looking at several other research questions, including: * What side effects may happen from taking the study drugs * Does linvoseltamab combined with dupilumab affect other types of antibodies in the blood at different times * How much study drug(s) is in the blood at different times